1. Field of the Invention
The present invention relates to a card-type electronic device, such as a memory card and, in particular, to the package structure of a cardtype electronic device of the type which has a card contact edge section for an input/output interface at an end thereof.
2. Description of the Related Art
As an example of a card-type electronic device, a memory card will be described. In a generally known conventional memory card package structure, a printed circuit board, on which memory devices, etc. are mounted, is contained in a shielding case comprising two (front and back) metal plates and a plastic frame. Adoption of a sandwich structure, in which the printed circuit board is placed between the two metal plates, proves particularly effective in protecting against radiation with EMI (electromagnetic interference) in the case of built-in memory devices such as SRAMS. Such a structure helps to protect data from deterioration, thereby attaining an improvement in terms of reliability.
However, the above-described memory card structure has the following problems:
(1) Due to the card structure in which the printed circuit board is sandwiched between the front and back metal plates, the card tends to be rather thick, which is rather inconvenient from the viewpoint of portability. PA1 (2) To prevent power short-circuiting, which is caused when the card is inadvertently inserted incorrectly, e.g. in a positioned reversed from its intended insertion position, it is necessary to provide, for example, a shutter on the card body, or a reverse insertion protecting mechanism in the card connector. This leads to an inconsistency in standardization of the memory card and a hindrance to generalization of the memory card. Further, due to the resulting increased production time, a reduction in cost is difficult to achieve.